The Canon EF 28mm f/2.8 Lens is both light in weight and light on your wallet. Measuring 2.6 x 1.7" (66 x 43mm) long and weighing 6.6 oz (186g), this lens qualifies for the tiny lens category.
I found the Canon EF 28mm f/2.8 Lens to be similar to the Canon EF 24mm f/2.8 Lens and the Canon EF 35mm f/2 Lens in build quality and size. The small size is great. The build quality is not great - though acceptable to me for a lens of this stature.
Lacking USM (Ultrasonic Motor), the 28 f/2.8 is mediocre in focusing speed and very high in noise level. Autofocusing is definitely audible but the speed is adequate for many applications. FTM (Full Time Manual) focusing is not a feature in this lens and manual focusing in MF mode is challenging. The focus ring is very small and has lots of play in it.
The 28 f/2.8's MFD (Minimum Focus Distance) is close - 12" (305mm), but not for a wide angle lens. MM (Maximum Magnification) is a near-the-bottom .13x.
Like the Canon EF 35mm f/2 Lens, the Canon EF 28mm f/2.8 Lens has a 5-blade aperture that yields pentagram-shaped out-of-focus highlights when the lens is stopped down. The result is not terrible - but is not great either.
The 28 f/2.8 is sharp wide open in the center with little noticeable improvement when stopped down. Wide open corners show softness even on a 1.6 FOVCF body due to a curved plane of sharp focus. Corner sharpness is markedly improved by f/4. Light fall-off is noticeable on the corners when shot wide open even on a 1.6x FOVCF body. Full frame camera body users will still see some corner shading at f/8.
The 28mm f/2.8 has noticeable CA (Chromatic Aberration) and some barrel distortion. Color and saturation are good.
Canon's other current 28mm prime, the Canon EF 28mm f/1.8 USM Lens, is the most logical comparison lens. Even though smaller and less expensive, the Canon EF 28mm f/2.8 Lens nearly keeps up with the f/1.8 in sharpness. The f/1.8 obviously has wider apertures available, but even stopped down to f/2.8, the f/1.8 is not much sharper than the f/2.8 lens. The 28mm f/1.8 is sharper in the corners, but at identical apertures, these lenses are not very dissimilar. What is noticeably different is the corner shading on the 28mm f/2.8. Corner darkening is the most significant differentiator when comparing images taken with these lenses. The f/2.8 has a little more barrel distortion than the f/1.8. Of course the f/1.8 is better built and has USM AF with FTM (Full Time Manual) focusing. I regard the Canon EF 28mm f/1.8 USM Lens, as the better lens, but the better performance and build are not lost on the price.
The small size of the Canon EF 28mm f/2.8 Lens makes it a good travel lens. It certainly does not take up much room in the luggage - and does not cause a catastrophe if lost or damaged.
The EF 28mm f/2.8 also makes a good second lens to carry when using one of the zooms such as one of the Canon 70-200 L Lenses as a primary lens. The 28 f/2.8 also makes a good backup lens to a more expensive primary use lens.
The Canon EF 28mm f/2.8 Lens is a decent lens for the price.